Direct growth of carbon nanotube junctions by switching source gases in a continuous chemical vapor deposition

A new method is used to directly grow carbon nanotube (CNT) junctions with two different structures through a continuous chemical vapor deposition (CVD) process. CH 4 /B 2 H 6 /H 2 and CH 4 /H 2 source gases were used as the feeding gas, respectively. By switching between different source gases in the CVD process, the junctions composed of boron-doped and pure CNTs were prepared. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the structure and composition of such junctions. The results show that each junction is having a bamboo boron-doped CNT at one side and a hollow CNT at another side, and the two different structures are connected with each other successfully.